Ya just answered your question if ya improve your exhaust air flow and not replacing your stock JET ya starve your carb of fuel'''and AIR''' motor will run rough.'''' BY INCREASING FUEL AND AIR FLOW AND EXHAUST FLOW It more economy and performance!!!Now if ya don't change your pipes and keep it stock keep the jet stock BUT!!!if you increase your exhaust flow through a header pipes ,and keep same air cleaner and stock jet, you will be sucking air and fuel trying to keep up with it and will lose power and get POOR GAS MILEAGE sometime bigger is better

huskerbob wrote:
Ya just answered your question if ya improve your exhaust air flow and not replacing your stock JET ya starve your carb of fuel'''and AIR''' motor will run rough.'''' BY INCREASING FUEL AND AIR FLOW AND EXHAUST FLOW It more economy and performance!!!Now if ya don't change your pipes and keep it stock keep the jet stock BUT!!!if you increase your exhaust flow through a header pipes ,and keep same air cleaner and stock jet, you will be sucking air and fuel trying to keep up with it and will lose power and get POOR GAS MILEAGE sometime bigger is better

Thank You for your insight Robert, have a great day!

That dog don't hunt to well!!! Alot of bikes with aftermarket pipes with out rejetting!!! My son is running V&H longshots no baffles, stock carb and aircleaner and our fuel mileage is about the same... Now if you go to a bigger airflow on your carb. It will run like crap, and need to be rejetted to compensate for the added airflow.. Just pipes it is not needed!!!!! Although some dealers try to sell you a rejet when you change pipes.. Happened to me as far back as 1980. Said no thanks will try it without jetting and the bike ran great...over 100k before getting rid of it.

Agpilot wrote:
That dog don't hunt to well!!! Alot of bikes with aftermarket pipes with out rejetting!!! My son is running V&H longshots no baffles, stock carb and aircleaner and our fuel mileage is about the same... Now if you go to a bigger airflow on your carb. It will run like crap, and need to be rejetted to compensate for the added airflow.. Just pipes it is not needed!!!!! Although some dealers try to sell you a rejet when you change pipes.. Happened to me as far back as 1980. Said no thanks will try it without jetting and the bike ran great...over 100k before getting rid of it.OK ya got what your son said fact is if you have header pipes
on any motor your increasing exhaust flow dose that sound right or why would you do it SO increase exhaust has no effect on fuel USE what ever''' YOUR DOGS BARKIN UP THE WRONG TREE?'''''Now it will run that way!!!!! but WHY would you add headers to increase exhaust flow then restrict fuel, and air flow, by not going after market? PLUS how hard are you making that motor run. Believe now or pay for it later ?I don't care I 've done it this way racing stock car in high school till today .that me it a matterof ''''PERFORMANCE''''''.Also I do my own work I don't need a dealer opinion.42-45MPG PIPE AIR CLEANER BIGGER JET 31''FRONT PULLEY 18''FRONT WHEEL

My son don't just say that! We ride side by side a lot gassing at the same spots and he will Constantly run about 2 to 3 mpg better than mine. We tour together and have rode 1000's of miles checking our mileage.. I know what I am talking about... these guys don't need to be told that you have to rejet with aftermarket pipes just not so!!! There is enough misinformation out there already!You have to increase the mass airflow to your carb before rejetting is necessary!!!! I rode a GL 1100 With four stock cv carbs, and Cobra Headers over 110k with out any problems..

Agpilot wrote:
My son don't just say that! We ride side by side a lot gassing at the same spots and he will Constantly run about 2 to 3 mpg better than mine. We tour together and have rode 1000's of miles checking our mileage.. I know what I am talking about... these guys don't need to be told that you have to rejet with aftermarket pipes just not so!!! There is enough misinformation out there already!You have to increase the mass airflow to your carb before rejetting is necessary!!!! I rode a GL 1100 With four stock cv carbs, and Cobra Headers over 110k with out any problems..Read the post I said you don't have to rejet but if ya want best """"""""PERFORMANCE again PERFORMANCE""""""all three is needed .#1 My word and buck might get ya a can of coke but 42-45 mpg with my modifications speaks for itself

Agpilot wrote:
My son don't just say that! We ride side by side a lot gassing at the same spots and he will Constantly run about 2 to 3 mpg better than mine. We tour together and have rode 1000's of miles checking our mileage.. I know what I am talking about... these guys don't need to be told that you have to rejet with aftermarket pipes just not so!!! There is enough misinformation out there already!You have to increase the mass airflow to your carb before rejetting is necessary!!!! I rode a GL 1100 With four stock cv carbs, and Cobra Headers over 110k with out any problems..

As a dealer tech I will vouch for what Agpilot has written. The exhaust does not typically alter the A/F ratio out of spec. Airbox mods on the other hand can and most often do result in A/F ratio problems. The opinions that a rejet is necessary is most often from those looking for power gains. Pipes and a rejet almost always results in increased power and sound levels. Factory engines are lean to meet emission requirements and will benefit from added fuel under most conditions but the need for more fuel is not necessary.

As a dealer tech I will vouch for what Agpilot has written. The exhaust does not typically alter the A/F ratio out of spec. Airbox mods on the other hand can and most often do result in A/F ratio problems. The opinions that a rejet is necessary is most often from those looking for power gains. Pipes and a rejet almost always results in increased power and sound levels. Factory engines are lean to meet emission requirements and will benefit from added fuel under most conditions but the need for more fuel is not necessary.[/quote] 100 AGREE will add power=performance somebody got it

I wasn't questioning the fact that a bak and jetting plus pipes would give you more performance. Mine has the aforementioned, but still does not get the mileage the stock one does.. this paragraph in your post is what I had conflict with..

( BUT!!!if you increase your exhaust flow through a header pipes ,and keep same air cleaner and stock jet, you will be sucking air and fuel trying to keep up with it and will lose power and get POOR GAS MILEAGE sometime bigger is better)

Guys,chk out yamaha's mpg rating i cut & pasted from the 1700 R*'s spec sheet .

Yamaha rates the 1700 R8 for 36mpg on avg.

Yes some can do better then 36mpg on avg esp when riding 1 up/flat roads/no bags or bags not loaded/slower cruise speeds lke 60-65mph/no headwinds/conservative riding- throttle use.

But with the mfg/yamaha stating on avg 36mpg for the 1700 R* is where it should be it doesnt look like most people are doing that bad running low to mid 30's (33-35mpg) on avg when yamaha states a 36mpg rating for the r* i pasted below.

And this spec if for EFI R* that should do better then carb'd R* becasue EFI runs cleaner/can control fuel mixture better then a carb in most cases.

So if your Carb'd R*s are running well & getting 32-35mpg on avg not seeming to run rich or smeeling like it running rich /plugs looking good - med to very light tan color not looking dark brown or black like running too rich i would not worry about it.

See below for Yamah's mpg spec on FEI 1700 R* i cut & pasted below.

Scott
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ENGINE
Engine 102 ci, air-cooled, 48° V-twin, pushrod OHV, 4-valves / cylinders

Displacement 1670 cc

Bore x Stroke 97 x 113 mm

Compression Ratio 8.3:1

Fuel System Fuel injection

Fuel Capacity 5.3 gal.

MPG Rating 36 mpg

Ignition TCI

Clutch Multi-plate wet